sendfrom and transaction fees

[TT]

I've noticed that if I've set transaction fees to 0.00 in my preferences and config file, when I try to send
bitcoin via the GUI, it sometimes prompts me if I want to pay a transaction fee of .0005 and sometimes
doesn't prompt me and sends with no transaction fee. I have the following questions:

1) Why does it only prompt me sometimes and on what does this depend?

2) I've noticed that when I make the call to sendfrom via the JSON-RPC API, I don't get prompted. It will just
assume I want to pay the .0005 transaction fee. Is there a way to get notified of this from the API before
committing to sending? Is it capped at .0005? Could it ever be higher than that? Is there a way to override
the GUI preferences and the config file settings and choose a specific transaction fee via the API and have
the call fail with an appropriate error message if the transaction fee is too low?

[1715279407]

1715279407

[SHlFT]

it charges a fee when you are sending "new" coins

[jh1523]

How "new" is "new" - or how "old" do they need to be so they're not "new" anymore?

[SHlFT]

"new" coins are coins are you just got from someone.
the fees are in place so no one can flood the network with penny transactions.


"old" coins are coins that's usually have 10+ Confirmations

[RJau]

thanks for the heads up.  I was confused why I only sometimes get this fee.